铁道标准设计2016，Vol.60Issue(9)：9-15,7.DOI:10.13238/j.issn.1004-2954.2016.09.003
简易轴向拉伸试验仪设计及试样合理尺寸的试验研究
The Design of Simple Axial Tensile Testing Instrument and Experimental Study of Reasonable Sample Size
摘要
Abstract
On account of the defects and shortcomings of the existing geotechnical tensile instrument, a set of simple axial tensile testing instrument is designed and improved. By the design of adjustment bolts on the four corners and fixtures, the frictional resistance and end stress concentration are eliminated, and the control of axial line prevents sample eccentric tension to fulfill axial tensile tests of rectangular specimens of different size. As there is no unified standard currently for sample size, a tensile device is designed test the samples with different cross section and slenderness ratio so as to determine specified sample size and analyze the influence of sample size on the tensile properties,. The test results are as follows:when ω=18. 0%, ρd =1. 30 g/cm3 , the average tensile strength value is between 14. 2 ~14. 6 kPa and the average displacement limit value is 8 ×10-2 ~9 ×10-2 mm of samples with different cross section;when ω=22. 0%,ρd =1. 45 g/cm3 , the average tensile strength value of the samples with different slenderness ratio is between 14. 4~14. 9 kPa and the relation between the average displacement limit value and slenderness ratio can be expressed as b=9. 706 7 × ( l/a )-6. 97 . The analyses results show that: when the sample physical conditions are the same, tensile strength values are not affected by cross section and the slenderness ratio whether the moisture content is less or greater than the omega plastic limit, and when the water content is below the plastic limit, the limit tensile displacement doesn’t change with change of the section of specimen; when the water content is higher than plastic limit, the correlation of the limit tensile displacement with slenderness ratio tends to be increasing linear. The calculation of the poor and the standard deviation of tensile strength of each group’s samples and the analysis of the discreteness data suggest that the reasonable specimen size is 2. 5 cm for section length and 3 for slenderness ratio with respect to the difficult degree of actual sample preparation and the amount of soil, which may provide reliable basis for future research on tensile strength of soil.关键词
黄土/抗拉试验/摩擦阻力/应力集中/合理尺寸Key words
Loess/Tensile test/Frictional resistance/Stress concentration/Reasonable size分类
建筑与水利引用本文复制引用
叶朝良,何世鑫,侯艳乐..简易轴向拉伸试验仪设计及试样合理尺寸的试验研究[J].铁道标准设计,2016,60(9):9-15,7.基金项目
国家自然基金项目(50978172) （50978172）
铁道部科技研究开发计划项目(2010G018-B-4) （2010G018-B-4）
国家大学生创新创业训练计划(201410107018) （201410107018）
